1. Field of the Invention
This invention relates to a method for producing anti-counterfeit paper. Such processes of this type, generally, add a certain percentage of wood fiber lumens which have been loaded with one or more fluorescent agents. These wood fiber lumens would look normal under regular light, but will glow when exposed to various manners of radiation.
2. Description of the Related Art
Traditionally, counterfeiting has been associated with the illicit production of currency. Today, however, there is a significant loss to manufacturers by counterfeiting of software, compact discs, cigarettes, video tapes, etc. This type of counterfeiting costs companies millions of dollars of lost revenue. Furthermore, these counterfeit items are usually made cheaply, thereby causing an unsuspecting consumer to question the manufacturers' quality.
Without a doubt, it is in the best interest of a company to eliminate counterfeit products, from an economic and public perception point of view.
Manufacturers have several different options at their disposal to combat counterfeiting. These include watermarks, specialized printing, the use of holographic labels, the use of synthetic fibers or additives, etc. These anti-counterfeiting techniques are described below.
Watermarks consist of impressing a design into the wet fiber web prior to couching the paper. Since this process is done early in the process, it arranges some of the fiber within the paper. This arranging of the fiber makes watermarks difficult to counterfeit.
Watermarks are used extensively in United States and European currencies and security documents. Other inventors have worked to increase the security of the watermarking process by controlled deposition of the fiber during the paper forming process and placing individual, unique watermarks on each piece of paper.
The use of watermarks is ideally suited for thin papers such as currencies, bank checks, etc., which are translucent. Unfortunately, the use of watermarks on thick papers and paperboard is of less utility because of the low transmission of light. A watermark on these thicker papers would not be readily apparent as in thinner, translucent papers.
Complicated printing techniques have also been traditionally used in security documents and currencies. These are typically lifelike portraits and intricate designs. Additionally, specialty inks, blended exclusively for these enduses, have extensive use in the security document sector. These specialty inks include everything from using multiple colors, to the use of high intensity ultraviolet light to create a pattern fluorescing in visible or ultraviolet light. However, the advent of high quality, color photocopiers have made the use of special ink colors and intricate designs less of a barrier to the counterfeiter.
In response to the increased ingenuity of the counterfeiters, microprinting was developed. Microprinting is a technique where messages, etc., are finely printed on a material. To the naked eye, the messages appear to be a simple line, but under magnification, the messages are revealed. This technique makes counterfeiting of the material more troublesome because the printing technique is difficult to do. However, the drawback to this microprinting technique is that it is relatively easy to acquire a printing press. Also, one can set up this printing equipment anywhere and keep it well hidden.
Holographic labels are also used extensively as an anti-counterfeit device. These labels have an image impressed into them which changes dependant on the point of view. A familiar example of these labels is the shiny image on credit cards. While these are effective as an anti-counterfeit device, they are expensive to produce and keep track of.
Placing dyed synthetic fibers into the printing substrate has been practiced for many years as an anti-counterfeit device. A common example is the paper used for US currency which has blue and red synthetic fibers in it. Though effective, it has a significant drawback because it can only be used in specific applications. For example, currency paper would not be suitable for general printing because the dyed synthetic fibers would detract from the images and/or printing.
Also, the related art contains references to planchettes which are tiny disks that appear on the paper. The disks are usually made from wet strength paper, however, plastic is sometimes used. The planchettes can be visible, invisible, ultraviolet responsive, etc. Additionally, the planchettes can be formulated to contain a portion of a color changing compound then incorporated into the paper. When the second portion of the color changing compound is applied, the planchettes change colors. Exemplary of such prior art is U.S. Pat. No. 4,037,007 ('007) to W. A. Wood, entitled "Document Authentification Paper".
While planchettes are an effective anti-counterfeiting measure, they do have several drawbacks. The primary one is that they can interfere with the printing process. Many inks used in the printing process are tacky. This tackiness can pull-off loose planchettes, thereby, causing a poor print. If this happens, the press must be stopped to clean up the loose planchettes.
Finally, some manufacturers have used fibers dyed with a fluorescent agent. These fibers are not readily apparent under normal light, however, under ultraviolet light these fibers glow. Exemplary of such prior art is U.S. Pat. No. 2,379,443 ('443), entitled "Process of Manufacturing Identifiable Paper", by Kantrowitz et al.
While the '443 patent describes a process whereby a percentage of chemically treated fibers are dispersed into fiber furnish prior to the papermaking process, the chemically treated fibers are indistinguishable from normal fibers until the paper is treated with a solution which reacts with the chemically treated fibers to produce an irreversible color change.
While the '443 patent describes the use of ultraviolet radiation as a means to cause chemically treated fibers to fluoresce, there are two major differences between the '443 patent and the present invention. The first such difference is that the present invention uses a lumen loading technique, which will be described later, to place the fluorescent material or dye inside the fiber. The technique of the present invention also includes rinsing the excess fluorescent material from the outside of the fiber. The lumen loading technique of the present invention is performed to trap/contain the fluorescent materials inside the fiber thereby minimizing the amount of dye migrating from the paper.
Minimizing the migration of these materials is important for certain enduses such as pharmaceutical and food packaging. The reason is that fluorescent materials usually have some toxicity associated with them and, therefore, the excess exposure to the consumer should be keep to a minimum. By trapping/containing the fluorescent materials inside the fiber, it reduces the potential migration from the paper and into the drug or food being packaged, thereby reducing exposure to a toxic substance.
Even in other enduses where the potential for transfer of fluorescent material is low, it is always beneficial to minimize one's exposure to toxic compounds. Examples of these enduses include security papers, such as checks, banknotes, etc.
The second major difference between the 1443 patent and the present invention is that the '443 patent only discloses the use of materials that fluoresce when exposed to ultraviolet radiation. In contrast, the present invention discloses the use of materials that fluoresce under all manner of radiation, including, but not limited to, ultraviolet and infrared. By using different materials that fluorescence under different radiation sources, the present invention allows for multiple methods to verify that an article is genuine. For example, if a paper contains lumen-loaded fibers, according to the present invention , that fluoresce under ultraviolet and it also contains similarly treated fibers that fluoresce under infrared, then it is quite possible that the counterfeiter will miss one of the fluorescences and make an imperfect copy.
It is apparent from the above that there exists a need in the art for an anti-counterfeit technique that is inexpensive, effective and hard to copy. Furthermore, the technique should not interfere with print characteristics of the substrate and the coating operations. It is the purpose of this invention to fulfill this and other needs in the art in a manner more apparent to the skilled artisan once given the following disclosure.